FRITZ!Box 3390 Service - Knowledge Base

DSL throughput is too low

The FRITZ!Box displays the actual DSL speed of the DSL line on the user interface under "Internet > DSL Information > DSL" in the "Current throughput" line. According to this, the current throughput is significantly lower than the speed specified in your DSL service agreement with your DSL provider.

Cause

The throughput of the DSL connection primarily depends on the length and quality of the access line. Faults in the cabling or problems with the Internet service provider's exchange (DSLAM) can also affect it.

Note:With many DSL lines, you will not be able to fully achieve the guaranteed throughput. Therefore, DSL providers say that they offer DSL speeds of "up to" a certain value.

Important:Some of the settings described here are only displayed if the advanced view is enabled in the user interface. The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS.

Simply proceed as described below. After each measure, check whether the issue persists.

1 Checking the cabling

Mistakes in the cabling can often be overlooked, but they can significantly reduce the DSL speed. Therefore, check the wiring in your home:

Make sure that the FRITZ!Box is connected correctly to your DSL line. Remove the following:

You can find the maximum speed set for your DSL line on the "DSL" tab in the "Max. DSLAM throughput" line. Compare this throughput with the speed specified in your DSL service agreement with your DSL provider.

If the speed specified in your DSL service agreement is higher than the speed set for your DSL line:

Contact your DSL provider.

Testing the DSL speed with a different DSL modem

With many DSL lines, you will not be able to fully achieve the speed guaranteed by your DSL provider. To check whether the quality of your DSL line is limiting the throughput or whether it is due to a technical issue, use a different DSL modem to test the DSL speed:

Important:Test the other modem soon after you finish testing the FRITZ!Box to ensure that you test it under the same conditions.

Disconnect the FRITZ!Box from the DSL line.

Connect a different DSL modem to the DSL line.

Test which DSL speed you achieve with the other DSL modem.

If the DSL speed is also significantly lower than the speed guaranteed by the provider when you use a different DSL modem: